This invention relates in general to wheelchairs. More particularly, this invention relates to a selectively displaceable camber assembly for preselecting camber angles for wheelchair drive wheels.
Wheelchairs are well known forms of transportation that increase the mobility of the physically impaired. Wheelchairs are typically relatively small, single-person conveyances that generally comprise a seat supported by a frame which, in turn, is supported by two oppositely disposed drive wheels and front casters. The drive wheels are usually located behind the center of gravity of the wheelchair occupant and the front casters are swivel-mounted to the wheelchair frame to permit the occupant to maneuver the wheelchair with greater ease. The wheelchair is maneuvered by differentially driving the drive wheels. The drive wheels may be manually driven or power driven. The drive wheels may be cambered so that the distance between the drive wheels at ground level is greater than the distance between the drive wheels at the level of the wheelchair seat. The camber angle increases the stability of the wheelchair, and the inward tilt of the drive wheels at the level of the wheelchair seat enables the occupant of the wheelchair to propel the wheelchair with greater comfort because the occupant's arms fall closer to the occupant's body.
In order to meet the needs of the physically impaired, wheelchairs must be versatile. Wheelchairs must be easily and readily adapted to accommodate the particular size and shape of the occupant. Wheelchairs must also be versatile in adapting to both ambulatory and recreational travel. Moreover, wheelchairs must be sufficiently durable to provide comfortable transportation over obstacles or irregular surfaces.
A need exists for a camber angle adjustment assembly for adjusting the camber angle of wheelchair drive wheels in accordance with the various purposes for which the wheelchair is used. Cambered drive wheels provide stability for wheelchairs as the wheelchairs are turned about comers and help to prevent the wheelchair from tipping over. The camber angle for normal usage is generally in the range of about 0 to 3 degrees, while the camber angle for recreational activities is generally in the range of about 6 to 15 degrees, and possibly more at times.
The disadvantage of wheelchairs having cambered drive wheels is that wheelchairs having cambered drive wheels may have difficulty negotiating narrow passageways. One solution to this problem is to have different wheelchairs; for example, one wheelchair without cambered drive wheels and one with cambered drive wheels. This solution, however, would prove to be too costly for the average wheelchair occupant. An alternative solution would be to provide a wheelchair in which the camber angle of the drive wheels may be changed to meet the various needs of the wheelchair occupant. Changing the camber angle, however, is often time consuming in that it may require numerous difficult mechanical trial and error adjustments to avoid undesirable misalignment of the castors relative to the drive wheels and the ground.